The Minnesota Department of Natural Resources warns ice anglers, snowmobilers, skiers and other outdoor enthusiasts to use caution when going onto any lake covered or partially covered with ice, especially those that feature aeration systems.

”Open water areas created by aeration systems can shift or change shapes depending on weather conditions," said Marilyn Danks, DNR aquatic biologist. "Leaks may develop in air lines creating other areas of weak ice or open water."

Aeration systems are generally operated from the time lakes freeze until ice break-up in the spring. They help prevent winterkill of fish, but they also create areas of open water and thin ice, which are significant hazards.

Two types of signs are used to post aerated lakes: “Thin Ice” and "Warning” signs. The person who applies for the permit (permittee) is to maintain “Warning” signs at all commonly used access points to the lake. This sign warns people approaching the lake that an aeration system is in operation and to use extreme caution.

The permittee must also put up “Thin Ice” signs to mark the area’s perimeter. Some municipalities may have ordinances that prohibit entering into the thin ice area and/or prohibit the night use of motorized vehicles on lakes with aeration systems in operation. These local regulations are often posted at accesses where they apply.

Aeration systems are inspected for safety and compliance with regulations by permittees and DNR personnel. For more information, call a regional fisheries office or the DNR Information Center at 651-296-6157 or toll-free 888-646-6367, info.dnr@state.mn.us.

The following is a list of the approximately 280 lakes that will likely have aeration systems in operation this winter.

When there are lakes in the county with the same name as the aerated lake, the nearest town is shown in brackets. Names in parentheses are alternate lake names. Those names followed by an asterisk are newly aerated lakes.